Simple Interest
Math MCQs

Question :    Calculate the amount due if Richard borrowed a sum of $3600 at 10% simple interest for 4 years.

Correct Answer  $5040

Solution & Explanation

Solution

Given,

Principal (P) = $3600

Rate of Simple Interest (SI) = 10%

Time (t) = 4 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% per annum.

Method (1) Using Formula

Calculation of Simple Interest

Formula to Calculate Simple Interest

Simple Interest (SI) = Principal × Rate × Time

Thus, Simple Interest (SI) = $3600 × 10% × 4

= $3600 ×¹⁰/₁₀₀ × 4

= ^{3600 × 10 × 4}/₁₀₀

= ^{36000 × 4}/₁₀₀

= ¹⁴⁴⁰⁰⁰/₁₀₀

= $1440

Thus, Simple Interest = $1440

Calculation of Amount

The total money paid to the lender by a borrower is called the Amount.

In other words, sum of priciple and interest is called the Amount.

Formula to Calculate the Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $1440

= $5040

Thus, Amount to be paid = $5040 Answer

Method (2)

Calculation of Amount when Principal, Rate of Simple Interest and Time are given

Calculation of Amount directly using Principal, SI, and Time

Formula to calculate the Amount

Amount (A) = Principal (P) + Principal(P) × Rate of Interest (SI) × Time (t)

⇒ A = P + PRT

Here in the question, P = $3600

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 4 years

Thus, Amount (A)

= $3600 + ($3600 × 10% × 4)

= $3600 + ($3600 ×¹⁰/₁₀₀ × 4)

= $3600 + (^{3600 × 10 × 4}/₁₀₀)

= $3600 + (^{36000 × 4}/₁₀₀)

= $3600 + (¹⁴⁴⁰⁰⁰/₁₀₀)

= $3600 + $1440 = $5040

Thus, Amount (A) to be paid = $5040 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $3600, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3600

= ^{10 × 3600}/₁₀₀

= ³⁶⁰⁰⁰/₁₀₀ = $360

Thus, simple interest for 1 year = $360

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $360 × 4 = $1440

Thus, Simple Interest (SI) = $1440

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $1440

= $5040

Thus, Amount to be paid = $5040 Answer

Similar Questions

(1) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 8% simple interest?

(2) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 5% simple interest?

(3) Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 2% simple interest.

(4) Calculate the amount due after 10 years if Sarah borrowed a sum of $5850 at a rate of 2% simple interest.

(5) Calculate the amount due if Susan borrowed a sum of $3650 at 2% simple interest for 3 years.

(6) William had to pay $3920 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(7) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 6% simple interest for 7 years.

(8) How much loan did Karen borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6545 to clear it?

(9) In how much time a principal of $3200 will amount to $3840 at a simple interest of 4% per annum?

(10) Anthony took a loan of $6600 at the rate of 9% simple interest per annum. If he paid an amount of $11352 to clear the loan, then find the time period of the loan.